WARNING! Here is a link to this guys experience with his M1 Garand with Herters ammo :o
http://bearingarms.com/m1-garand-blew-bad-ammo-saga/ (http://bearingarms.com/m1-garand-blew-bad-ammo-saga/)
BE WARNED ABOUT THIS AMMO~!~ ???
M1 Garands aren't even supposed to use a lot of regular store bought ammo, as they have more pressure than a standard operating rod can stand.
I know my Hornady reloading manual has two 30.06 sections, one regular and one M1.
Where was it determined to be the ammo? I don't know much about this rifle, but see in the comments asking why he is shooting .308 out of a 30-06.
There are some chambered in .308 I think they call them a Tanker model. :-[
There are lots of various Garands that shoot 308. The Navy switched some to 308 before the moved on to a different rifle. And many guys have their garands re-barreled to 308 just for ammo availability. The "tanker" conversion another example of a garand that is commonly in 308.
I personally don't run ANY ammo in my garands that I didn't personally reload or buy from the CMP. But, that is just me.
Yes, there are some differences in what the 30'06 M1 Garand and what is loaded for Bolt action guns...
Here is some data for the 30'06 M1 Garand from NRA
http://web.archive.org/web/20000620055732/home.att.net/~Masterpo/M1load.htm (http://web.archive.org/web/20000620055732/home.att.net/~Masterpo/M1load.htm)
Not all brass of the '06 is equal, commercial vs. mil spec.
It is not that commercial .30-06 ammo is higher pressure than that intended for the Garand, but that it uses the wrong burn rate powder and the pressure is too high at the gas port. This is an important distinction to understand when loading for the Garand.
Something to keep in mind about the Herters Steel Cased ammo, it has a varnish on it that can come off and build up on the inside of the chamber. Usually, you begin to notice when the rounds get hard to extract in a bolt gun. In a non-bolt gun, essentially, over time, the chamber gets tighter and tighter as more and more varnish builds up.
It is a pain in the ass to clean out of the chamber btw ;D